Many types of human-powered tricycles are known. The main advantages of tricycles over a standard bicycle are stability and safety: the fact that there are three wheels in a tricycle, instead of two, enables the rider to load extra weight on the tricycle, such as small children or shopping bags, and to maintain the child or the bags on the tricycle without risk of falling, even when the tricycle is at a full stop.
A major problem with available types of tricycles, as carrying vehicles, is their large size and structure, making them difficult and sometimes forbidden to use in indoor places and in small and crowded places such as shops, supermarkets, malls, coffee bars, elevators, buses, trains and even busy street pavements and small apartments.
Japanese Patent Document JP2005088606 describes a folding tricycle, which may transport a load or a child thereon, and can be used as a cart for a load or a buggy in a folded state. The folding tricycle has two front wheels and one rear wheel in order to improve the stability in a traveling mode. A mounting base capable of mounting a load or a child is provided between the two front wheels. When folded, the tricycle has a shortened wheel base for use as a cart or buggy.